Plasticizers for vinyl chloride polymers

ABSTRACT

In production of solid films (e.g. a floor covering wear layer) from vinyl chloride polymer plastisols, good physical properties of the plastisols and films are provided by use of a plasticizer containing 50-90% prime ester at least about 40 parts per hundred parts by weight of which is aromatic diester selected from alkyl benzyl succinates, glutarates and mixtures thereof, up to 20% hydrocarbon boiling at 200°-325° C. and 10-50% non-aromatic diester having a molecular weight of 230-300. Using such a plasticizer, the plastisols and films can be conveniently plasticized with relatively small amounts of prime ester, and the films containing such small amounts of prime ester have unusually high stain resistance.

CROSS-REFERENCE TO RELATED APPLICATION

This is a continuation-in-part of copending application Ser. No. 972,762filed Dec. 26, 1978, now abandoned.

BACKGROUND OF THE INVENTION

This invention relates to plasticizers for vinyl chloride polymer filmsand plastisols used in production of such films. In particular, theinvention relates to plasticizers with which such plastisols and filmscan be made using relatively small amounts of plasticizing ester, and tothe production of highly stain-resistant vinyl chloride polymer films.Efforts to develop such films are especially important in the vinylfloor covering industry due to the much greater consumer appeal offlooring resistant to common stainants including shoe polish, mustard,road surfacing materials such as asphalt, etc.

In general, it is very desirable to produce plasticized vinyl chloridepolymer films without the costs of intensive mixing of polymer andplasticizer, e.g. in a Banbury mixer. Thus for economic reasons, theexpedient of plastisol application of vinyl chloride polymer films isemployed whenever feasible. In accordance with that technique, now wellknown in the art, finely divided vinyl chloride polymer (hereinafter"VCP") is essentially uniformly dispersed in an amount of plasticizersufficient to form a plastisol (normally at ambient temperature) ofviscosity low enough for reasonably rapid escape of entrained air andfor convenient casting of the plastisol on a solid surface where it willbe fused to form an essentially homogeneous, molten film and then cooledto solidify that film. In addition, the amount of plasticizer employedmust be sufficient to provide satisfactory plasticization of the film asshown by its flexibility, percent elongation at break, etc.

In general, plasticizers used in preparation of such plastisols areadvantageously carboxylic acid esters such as alkyl benzyl phthalates,dialkyl phthalates, alkyl benzoates, etc. Various diluents, e.g.hydrocarbons which flash off during plastisol processing, may helpmaintain a desirably low plastisol viscosity but not substantiallyenhance the plasticizing of the resulting film. In addition, use of anexcess of such diluents may contribute to other problems such as"blooming" from the film of soaps present in VCP from its production byemulsion polymerization. Thus a certain amount of "prime" ester (i.e.,ester which remains in the VCP film or other composition after fusingand solidification of the VCP plastisol) is normally considerednecessary in plastisol application of VCP, and it is usually expectedthat the required amount of such prime ester will be from 35 to 70 ormore parts per hundred parts by weight of the VCP. See, for example,"Vinyl Dispersion Coatings for Foam Floorings and Fabrics", L. G.Friedman, Soc. of Plastics Engineers, 28th Annual Technical Conference,pp. 226-31 (1971) and Vol. 3, Encyclopedia of PVC, Marcell Dekker, Inc.,New York and Basel, p. 1426 (1977).

Unfortunately, the staining tendency of the resulting VCP film istypically more or less proportional to the amount of plasticizing esterpresent in the film and consequently, it is highly desirable to identifyan ester-containing plasticizer composition which can be used to providean attractively low plastisol viscosity and good plasticization of theresulting film when used in amounts small enough to interfere relativelylittle with the natural stain resistance of the VCP. Thus it is anobject of this invention to provide a more efficient plasticizercomposition such that plastisol-applied films produced therewith aremore highly stain-resistant. Other objects are VCP compositionscontaining such a plasticizer composition and, in particular, arelatively small but adequately plasticizing amount of such aplasticizer composition. Another object is to provide VCP plastisolcompositions which can be cast in a film on a solid surface, fused andthen cooled to provide a solid, plasticized film (e.g. a floor coveringwear layer) having a high degree of stain resistance. Other objectsinclude the resulting stain-resistant floor covering wear layers andother solid films. Another object is the provision of a method forproducing such VCP plastisols and the stain-resistant floor coveringwear layers and other solid forms made from such plastisols. Otherobjects will be apparent from the following disclosure in which allparts and percentages are by weight except where otherwise noted and"phr" represents parts per hundred parts by weight of VCP in any givencomposition.

SUMMARY OF THE INVENTION

In accordance with this invention, the afore-described objects areachieved by use of a plasticizer composition containing by weight fromabout 50% to about 90% prime ester at least about 40 parts per hundredparts by weight of which is aromatic diester selected from alkyl benzylsuccinates, glutarates and mixtures thereof in which said alkyl containsfrom about 3 to about 6 carbon atoms, from about 10% to about 50%non-aromatic diester having a molecular weight from about 230 to about300 and, optionally, up to about 20% essentially non-olefinichydrocarbon boiling between about 200° and about 325° C. In addition,the invention provides VCP compositions comprising a plasticizing amountof such a plasticizer composition. Also provided are highlystain-resistant floor covering (e.g. vinyl sheet flooring) wear layersand other solid films prepared from such plasticized polymercompositions, and plastisols of such polymer compositions for use inproduction of such films. Also provided is a method for producing a VCPcomposition which can be used to prepare such highly stain-resistantfilms, which method comprises dispersing finely divided particles of thepolymer and a plasticizing amount of such a plasticizer composition.

DETAILED DESCRIPTION OF THE INVENTION

As used herein, the term "vinyl chloride polymer" or "VCP" includesvinyl chloride homopolymer (hereinafter polyvinyl chloride or "PVC") andvinyl chloride copolymers in which the structure of polyvinyl chlorideis interspersed with residues of other olefinically unsaturatedcompounds copolymerized therewith. Essential properties of the polymerstructure of polyvinyl chloride are normally retained if the monomersare at least about 60% vinyl chloride. Suitable comonomers include, e.g.maleic anhydride, vinyl esters such as vinyl acetate, and many others assuggested in U.S. Pat. No. 2,943,949 issued July 5, 1960 to R. K. Petry,the disclosure of which is incorporated herein by reference.

This invention further relates most advantageously, although notexclusively, to VCP compositions which are essentially unfilled, i.e.,not containing a substantial amount of the fillers (generally inorganic,e.g. clay, talc, CaCO₃, TiO₂, BaSO₄, asbestos, etc.) with which suchcompositions are commonly extended for various use such as rigid vinylasbestos floor tile and the like. Thus, the invention has particularapplicability to VCP compositions consisting essentially of VCP and aplasticizer therefor, which compositions are especially attractive foruse in production of transparent or translucent films which may alsocontain, if desired, minor proportions of conventional additives such ascolorants, stabilizers, etc., not incompatible with production ofplastisol-applied films from such compositions.

As aforesaid, this invention utilizes alkyl benzyl succinates,glutarates and mixtures thereof, i.e. diesters of succinic and/orglutaric acid in which a benzyl radical is directly attached to onecarboxy group of the acid and an alkyl radical is directly attached tothe other carboxy group of that acid. The alkyl radical in such diestersmay be from about C₃ to about C₆. In most embodiments it is preferablyfrom C₃ to C₅, and even more typically it is preferably C₄ (butyl).Branching of the alkyl radical is generally advantageous but notnecessary. In many embodiments, the descending order of alkyldesirability is isobutyl, n-butyl, sec-butyl, neopentyl, isopropyl andisoamyl. These diesters may be prepared as described in U.S. Pat. No.3,483,247 issued Dec. 9, 1969 to R. H. Mills. Diesters consistingessentially of either such glutarates or succinates can besatisfactorily employed in this invention as can blends of suchsuccinates and glutarates in virtually any proportions.

It has been discovered that such alkyl benzyl succinates and/orglutarates provide or assist in providing good plasticization of VCPplastisols and solid films made therewith, in many embodiments at lowenough total amounts of prime ester that the resulting films haveunusually high stain resistance. This invention is based on thediscovery that the use of such succinates and/or glutarates in theplasticizing of such films and plastisols, especially at such relativelylow levels of prime ester, is greatly facilitated by inclusion of thesuccinates and/or glutarates in a plasticizer composition containingfrom about 50% to about 90% prime ester including such succinates and/orglutarates and from about 10% to about 50% non-aromatic diester having amolecular weight from about 230 (preferably at least about 260) to about300 (preferably not more than about 290).

Examples of such non-aromatic diester include various dialkyl esters ofalkane dicarboxylic acids such as dialkyl (e.g. dibutyl or dihexyl)succinate and/or glutarate, dialkyl (e.g. dibutyl) adipate and, usuallymost desirably, a texanol ester of C₃ -C₆ alkyl monocarboxylic acid suchas, e.g. one of the butyric acids. As used herein, "texanol" representsthe alcohol named 2,6,6,8-tetramethyl-4-oxa-3-oxo-nonan-7-ol underAmerical Chemical Society Chemical Abstract terminology and having thefollowing structural formula: ##STR1## Especially useful in someembodiments of this invention is the diester made by reaction of thatalcohol with isobutyric acid, referred to hereinafter as texanolisobutyrate (MW 286). In most embodiments of the invention thisnon-aromatic diester essentially completely volatilizes during fusing ofthe VPC plastisol, but there is generally no significant disadvantage ifsuch volatilizing is less than complete inasmuch as such diester canserve as an excellent secondary plasticizer and case-hardening ester andalso has good stain-resistance properties.

The plasticizers of this invention may be compositions consistingessentially of prime ester and the aforementioned non-aromatic diester.Optionally, however, and typically advantageously for reasons ofeconomy, such plasticizer compositions may also contain a minorproportion (preferably not more than about 20%) of a diluent whichfurther lowers the viscosity of VCP plastisols produced therewith butessentially completely volatilizes during fusing of the plastisol suchthat little or none remains in solid film produced from such plastisol.Desirably such a diluent is essentially non-olefinic hydrocarbon(s)boiling between about 200° and about 325° C. (preferably between about250° and about 300° C.). Advantageously, such diluent is predominantlycomposed of monocyclic alkylbenzenes containing from about 14 to about24 carbon atoms and in which each alkyl substituent on the benzene ringcontains from about 6 to about 16 carbon atoms (preferably from about 8to about 14, and most desirably from about 10 to about 12 carbon atoms).Most conveniently such alkylbenzenes are monoalkylbenzenes. Good resultsare obtained by use of diluent consisting essentially of suchalkylbenzenes, but such diluent may also satisfactorily contain a minorproportion of other hydrocarbons, e.g. paraffins and the like, which donot intolerably alter its characteristics of volatility and utility inthis invention.

Thus in general, the plasticizer compositions of this invention contain,and in preferred embodiments consist essentially of from about 50% toabout 90% prime ester, from about 10% to about 50% of the aforementionednon-aromatic ester and up to about 20% of such a hydrocarbon diluent. Inpreferred embodiments, those proportions are typically from about 60% toabout 80% prime ester, from about 10% to about 30% of the non-aromaticester and from about 5% to about 15% hydrocarbon diluent. Even morepreferred for most uses are plasticizer compositions in which thoseproportions are from about 65% to about 75% prime ester, from about 15%to about 25% of the non-aromatic ester and from about 5% to about 15%hydrocarbon diluent.

After thorough mixing of such a plasticizer and VCP, the resultingplastisol is cast in a film on a solid surface, fused on that surfaceand then cooled below its freezing point to provide a solid, essentiallyhomogeneous film which may be stripped from that surface or permitted toremain thereon for its intended end use, e.g. as a floor covering wearlayer. The techniques of producing solid VCP films by casting, fusingand cooling such plastisols are known in the art, and are to bedistinguished from production of "solid" vinyl tile made by dryblendingand calendaring a mixture of VCP and plasticizer. Most commonly inaccordance with this invention, plastisol is applied to the surface onwhich it will be fused by flow- or dip-molding, rotary screen printingor reverse-roll or knife coating. Normally the resulting film issemi-rigid. Although it is feasible to include a blowing agent in theplastisol, it is more common to omit a blowing agent such that theresulting film is essentially non-cellular.

Presently, an important utility of such plastisol-applied film is a VCPsheet flooring wear layer applied to a plasticized, foamable VCP gellayer which may be situated on any of various suitable solid substrates,for example asbestos or other paper impregnated with a binder (e.g.acrylic or SBR latex), suitable release paper, woven or non-woven (e.g.felted) fabric of organic and/or inorganic fibers, or sheetthermoplastic material. Normally such a wear layer is applied in athickness which, after fusing and cooling, is between about 0.2 andabout 0.9 mm. The multi-layered structure thus assembled is then passedthrough an oven in which it is heated to a temperature sufficient tofuse the two plasticized VCP layers. Techniques for the production ofsuch floor covering are well-known in the art. See U.S. Pat. Nos.3,293,094 and 3,294,108 issued Dec. 20, 1966 and 2,961,332 issued Nov.22, 1960 to R. F. Nairn et al. and 3,196,030 issued July 20, 1965 to R.K. Petry, the disclosures of which are incorporated herein by reference.

In general, the amount of plasticizer composition included in a VCPcomposition of this invention is a plasticizing amount, i.e. an amountsufficient to permit convenient plastisol application of VCP and providesuitably plasticized film produced therwith. Normally, such aplasticizing amount is at least about 30 phr, even more typically atleast about 35 phr and most commonly between about 35 and about 50 phr.As aforesaid, the plasticizer compositions of this invention areespecially attractive in that they facilitate the plasticizing of VCPfilms and plastisols using relatively low levels of prime ester at whichthe films have unusually high stain resistance. For example, inembodiments of the invention using prime ester consisting essentially ofthe aforementioned succinates and/or glutarates, the amount of primeester which is satisfactory from the standpoint of adequate VCPplasticization is typically less than 35 phr and in many instances neednot be more than about 30 phr. Usually in those embodiments the amountof such succinates and/or glutarates employed is at least about 20 phr,and best results are normally attained using at least about 25 phr,although there is considerable flexibility in the amount employeddepending on the use of diluents, secondary plasticizers, etc.

In other embodiments in which such succinates and/or glutarates are usedin combination with other prime ester, the succinates and/or glutaratesplasticize the VCP plastisols and films with such great efficiency thatwhen at least about 40% of the prime ester employed is such succinatesand/or glutarates, the total amount of prime ester required is generallyless than 35 phr and the resulting films are similarly characterized byunusually high stain resistance. In those embodiments in which suchsuccinates and/or glutarates are at least about 60% of the prime esteremployed, the total amount of required prime ester is generally not morethan about 30 phr and the resulting films are typically even moreexceptional in stain resistance.

Even in embodiments in which the amount of prime ester employed is 35phr or more and the succinates and/or glutarates make up less than about40% but a substantial proportion (e.g. at least about 5%) of the primeester employed, the succinates and/or glutarates replace enough of theother prime ester used therewith that the total amount of prime esterrequired for adequate plasticization is substantially less than thatnormally required without use of such succinates and/or glutarates. Forinstance, in plastisols and films in which about 50 phr of other primeester such as butyl benzyl phthalate or a mixture of texanol benzoatesis normally required, the inclusion of about 10 phr of theaforementioned succinates and/or glutarates typically lowers the amountof such other prime ester required for use therewith to about 30 phr andcorrespondingly lowers the total amount of prime ester required to about40 phr.

The following specific examples of this invention are included forillustration only and do not imply any limitations on the scope of theinvention.

PREPARATION OF PLASTICIZERS

Plasticizer A is prepared by thoroughly mixing 70 parts isobutyl benzylsuccinate, 20 parts texanol isobutyrate and 10 parts hydrocarboncomposed of 67.5% linear alkylbenzenes boiling at 274°-295° C. in whichthe alkyl is from C₉ to C₁₄ (99% C₁₀ -C₁₂) and 32.5% of a recycle stream(12% of such alkylbenzenes, 3% C₈ -C₁₆ olefins and 85% C₈ -C₁₆ paraffinswith the average being C₁₃) from production of such alkylbenzenes.Plasticizer B is prepared likewise except there is substituted for theisobutyl benzyl succinate an equal amount of a mixture of two partsisobutyl benzyl glutarate and one part isobutyl benzyl succinate.Plasticizers C, D and E are likewise prepared except that in each, anequal amount of n-butyl benzyl succinate, sec-butyl benzyl succinate orisopropyl benzyl glutarate, respectively, is substituted for theisobutyl benzyl succinate used in preparation of Plasticizer A.

For comparative purposes there are hereinafter used the followingcommercially available PVC plasticizers:

Plasticizer F--78% texanol benzyl phthalate and 22% dodecyl benzene;

Plasticizer G--60% texanol benzoate, 25% texanol dibenzoate, 14% texanolisobutyrate or benzoate and 1% texanol.

EXAMPLES 1-6

75 parts of a conventional paste-grade low-soap PVC of 1.4 inherentviscosity, 25 parts of a conventional PVC blending resin of 0.9 inherentviscosity and 57 micron mean particle size, 3 parts epoxidized soybeanoil and 2 parts Ba/Zn stabilizer are uniformly dispersed withmedium-shear, high-torque mixing in plasticizing amounts of PlasticizersA, B, F and G as shown in Table I. The resulting plastisols areidentically stirred in such a way as to minimize the entrainment ofadditional air and then deaerated in a stirred vacuum chamber in whichvisual observations of air release rates are noted. Initial viscosity ofeach plastisol is measured by Brookfield Viscometer Model HAT, #5spindle, in accordance with SPI procedure VD-T1 (1959). Results are inTable I.

                  TABLE I                                                         ______________________________________                                        PLASTISOLS                                                                    1          2      3      4    5    6    F    G                                ______________________________________                                        Plasti-                                                                       cizer   A      A      A    B    B    B    F    G                              phr Plas-                                                                     ticizer 40     44     48   40   44   48   48   48                             phr Prime                                      40.8-                          Ester   28     30.8   33.6 28   30.8 33.6 37.4 47.5                           Air     Fast   Fast   Fast Fast Fast Fast Med- Med-                           Release                                   Fast Fast                           Viscosity                                                                     rpm     Centipoises                                                           2.5     4480   3200   2240 4800 3200 2240 4480 5440                           5       3200   2400   1600 3360 2240 1600 4000 4800                           10      2480   1760   1280 2640 1840 1200 3600 4560                           20      1960   1400   1000 2120 1360 1000 3640 4560                           50      1600   1104    800 1712 1088  768 4048 5216                           100     1496   1016    720 1552 992   696 5328 6768                           ______________________________________                                    

Samples of plastisols 1-6, F and G are cast on aluminum plates in auniform 0.64 mm thickness. The cast films are fused by heating on arotating rack in a forced air oven at 180° C. for 210 seconds, afterwhich they are removed from the oven and allowed to cool. When the filmsare no longer tacky they are stripped off the plates. Portions of thefilms are subjected to measurements of 100% modulus (tensile stress at100% elongation), % elongation at break and tensile strength, all inaccordance with ASTM D412-75. The averages of triplicate measurementsare in Table II.

                  TABLE II                                                        ______________________________________                                               100% Modulus                                                                              % Elongation                                                                              Tensile Strength                               Plastisol                                                                            (kg/cm.sup.2)                                                                             at Break    (kg/cm.sup.2)                                  ______________________________________                                        1      115         262         225                                            2      102         275         213                                            3      86          290         196                                            4      110         272         226                                            5      95          291         212                                            6      82          299         198                                            F      167         240         244                                            G      137         260         236                                            ______________________________________                                    

Additional samples of plastisols 1-6, F and G are cast on a conventionalfoamable PVC flooring gel coat on an asbestos felt backing. Eachplastisol is cast in a film which, when fused at 205° C. for 130 secondsand then cooled below its freezing point, provides a wear layer ofuniform thickness between 0.31 and 0.38 mm on the floor covering. Thewear layers produced with plastisols 1-6, F and G are essentiallyequivalent in resistance to wrinkling. In comparative stain resistanceevaluations, DuPont Oil Yellow Dye (0.5% in odorless kerosene) isdripped onto a 2.5 cm.-square piece of #2 filter paper lyinghorizontally on a sample of each wear layer at room temperature untilsaturation of the paper. Thirty minutes later, the filter papers areremoved and the wear layer samples are blotted and wiped with mineralspirits. In parallel testing, a semi-solid road surfacing material ofmoderate staining tendency is spread with a spatula on another sample ofeach wear layer and, after thirty minutes, wiped off with mineralspirits. The stains remaining on the wear layer samples are thenvisually evaluated according to a scale on which one represents novisible stain and 12 represents severe staining. Duplicate samples arewrapped in aluminum foil and then oven-aged at 40° C. for 16 hoursbefore staining. Results are in Table III.

                  TABLE III                                                       ______________________________________                                               PLASTISOLS                                                                    Not Oven-aged                                                          Stainant 1      2      3    4    5    6    F    G                             ______________________________________                                        Yellow                                                                        Dye      1      1      1.5  1    1.5  2    4    2                             Road                                                                          Surfacing                                                                     Material 1.5    1.5    1.5  1.5  1.5  1.5  5.5  4                                      Oven-aged                                                            Yellow                                                                        Dye      3.5    5.5    6    4.5  6    6.5  6.5  4                             Road                                                                          Surfacing                                                                     Material 1.5    1.5    1.5  1.5  1.5  3    5.5  4.5                           ______________________________________                                    

EXAMPLES 7-14

In larger-scale tests, Plasticizers A-D, F and G are evaluated invarious plasticizing amounts in plastisol-applied PVC flooring wearlayers as described hereinbefore. Compositions of the plastisols andtheir Brookfield viscosities measured in accordance with SPI procedureVD-T1 (1959) after storage for seven days at 23° C. are in Table IV.

                                      TABLE IV                                    __________________________________________________________________________    PLASTISOLS                                                                    F.sub.2  G.sub.2                                                                          7   8  9  10  11 12 13 14                                         __________________________________________________________________________    Plasti-                                                                       cizer F  G  A   A  A  B   B  B  C  D                                          phr Plas-                                                                     ticzer                                                                              48 48 36  40 44 36  40 44 40 40                                         phr Prime                                                                     Ester 37.4                                                                             47.5                                                                             25.2                                                                              28 30.8                                                                             25.2                                                                              28 30.8                                                                             28 28                                         Viscosity                                                                     Data                                                                          rpm   Centipoises                                                             2.5   5440                                                                             6400                                                                             15,680                                                                            8000                                                                             4800                                                                             19,840                                                                            8960                                                                             5120                                                                             9280                                                                             6400                                       5     5120                                                                             5920                                                                             12,160                                                                            5760                                                                             3360                                                                             15,040                                                                            6720                                                                             3680                                                                             6880                                                                             4800                                       10    4720                                                                             5680                                                                              9,840                                                                            4560                                                                             2720                                                                             11,840                                                                            5200                                                                             2880                                                                             5520                                                                             3840                                       20    4720                                                                             5640                                                                              7,960                                                                            3640                                                                             2160                                                                              9,480                                                                            4360                                                                             2360                                                                             4360                                                                             3080                                       50    4992                                                                             6080                                                                              6,544                                                                            3024                                                                             1808                                                                              7,648                                                                            3552                                                                             1968                                                                             3584                                                                             2560                                       100   5712                                                                             6992                                                                              6,080                                                                            2840                                                                             1672                                                                              6,944                                                                            3272                                                                             1800                                                                             3272                                                                             2416                                       __________________________________________________________________________

The above plastisols F₂, G₂ and 7-14 are all medium in visual speed ofair release. Solid films and floor covering wear layers are prepared andevaluated as in Examples 1-6, F and G except that films of uniformthickness between 0.76 and 0.89 mm are cast on release paper rather thanan aluminum plate for the ASTM tests, oven aging is at 49° C. for sevendays and the stain resistance comparisons are carried out with cordovanshoe polish, mustard and road surfacing materials of moderate, heavy andvery heavy staining tendencies. ASTM test results are in Table V. Stainresistance comparison results are in Table VI.

                  TABLE V                                                         ______________________________________                                               100% Modulus                                                                              % Elongation                                                                              Tensile Strength                               Plastisol                                                                            (kg/cm.sup.2)                                                                             at Break    (kg/cm.sup.2)                                  ______________________________________                                        F.sub.2                                                                              165         261         243                                            G.sub.2                                                                              142         233         217                                            7      139         217         210                                            8      118         264         220                                            9      100         286         210                                            10     139         263         236                                            11     118         283         229                                            12      99         293         208                                            13     113         289         229                                            14     120         261         215                                            ______________________________________                                    

                  TABLE VI                                                        ______________________________________                                                PLASTISOLS                                                                    F.sub.2                                                                            G.sub.2                                                                              7     8   9   10  11  12  13  14                          ______________________________________                                                Not Oven-aged                                                         Cordovan Shoe                                                                 Polish    10     7.5    5.5 5   6.5 5.5 6   7   6.5 5.5                       Mustard   1.5    2      1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5                       Road Surfacing                                                                Materials                                                                     Moderate                                                                      Stainant  6      4      1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5                       Heavy                                                                         Stainant  10     9      2   2   2.5 2.5 2.5 3.5 2.5 3                         Very Heavy                                                                    Stainant  12     11     5.5 5.5 6.5 7   7.5 8   7   6.5                                 Oven-Aged                                                           Moderate                                                                      Stainant  6      5      2.5 2.5 3   3   3   3.5 2.5 3                         Heavy                                                                         Stainant  8.5    7.5    3.5 4   5   4   5   6   5.5 4                         Cordovan Shoe                                                                 Polish    11     10     8   8   8.5 8.5 8.5 8.5 8.5 8                         ______________________________________                                    

EXAMPLES 15-16

By procedure like those in the previous examples, Plasticizer E iscompared with Plasticizer B. Visual air release speeds of theplastisols, each of which contained 40 phr plasticizer (28 phr primeester) are medium. ASTM test results are in Table VII. Stain resistancecomparison results are in Table VIII.

                  TABLE VII                                                       ______________________________________                                               100% Modulus                                                                              % Elongation                                                                              Tensile Strength                               Plastisol                                                                            (kg/cm.sup.2)                                                                             at Break    (kg/cm.sup.2)                                  ______________________________________                                        15     123         235         216                                            (Plasti-                                                                      cizer B)                                                                      16     118         244         221                                            (Plasti-                                                                      cizer E)                                                                      ______________________________________                                    

                  TABLE VIII                                                      ______________________________________                                                        PLASTISOLS                                                    Road Surfacing Material                                                                         15         16                                               ______________________________________                                        Moderate Stainant 0.5        0.5                                              Heavy Stainant    1.5        1.5                                              Very Heavy Stainant                                                                             6.5        5.5                                              ______________________________________                                    

It will be apparent from the foregoing data that, compared with VCPcompositions containing other commonly-used plasticizers, typical VCPcompositions of this invention containing relatively low amounts ofprime ester provide plastisols which are advantageously pseudoplasticand plastisol-applied films of attractive physical properties includinglow 100% modulus, high % elongation at break and unusually high stainresistance.

EXAMPLE 17

In a separate evaluation of the non-aromatic diester constituent, thedeaeration, initial viscosity and stain resistance measurements inExample 2 are essentially duplicated in direct comparison with use of anequal amount (44 phr) of Plasticizer G (described hereinbefore) or oneof the following PVC plasticizers which each contain 70% isobutyl benzylsuccinate and 30% of the indicated dialkyl ester: Plasticizer H--diethyladipate (MW 202); Plasticizer J--dihexyl adipate (MW 314); andPlasticizer K--diisobutyl phthalate. Results are in Table IX.

                  TABLE IX                                                        ______________________________________                                                 PLASTISOLS                                                                    G.sub.3                                                                              17       H       J      K                                     ______________________________________                                        Plasticizer                                                                              G        A        H     J      K                                   phr Prime Ester                                                                          37.4-43.6                                                                              30.8     30.8  30.8   30.8                                Air Release                                                                              Fast     Slow     Slow- Slow   Slow                                                             Med.                                             Viscosity                                                                     rpm        Centipoises                                                        2.5        5440     2560     7360  3200   5760                                5          5120     2240     5760  2560   4960                                10         4880     1920     4640  2080   4240                                20         4960     1600     3680  1840   3640                                50         5312     1360     2912  1584   3168                                100        6288     1288     2536  1472   2984                                Road Surfacing                                                                Materials  (Not Oven-aged)                                                    Moderate                                                                      Stainant   2        0.5      1.5   3      1.5                                 Very Heavy                                                                    Stainant   10       6        7.5   8      9                                   ______________________________________                                    

I claim:
 1. A plasticizer composition consisting essentially of, by weight, from about 50% to about 90% prime ester at least about 40 parts per hundred parts by weight of which is aromatic diester selected from alkyl benzyl succinates, glutarates and mixtures thereof in which said alkyl contains from about 3 to about 6 carbon atoms, up to about 20% essentially non-olefinic hydrocarbon boiling between about 200° and about 325° C. and from about 10% to about 50% non-aromatic diester having a molecular weight from about 230 to about
 300. 2. Composition of claim 1 wherein said non-aromatic diester is essentially texanol ester of C₃ -C₆ alkyl monocarboxylic acid.
 3. Composition of claim 1 wherein the alkyl in said aromatic diester is from C₃ to C₅.
 4. Composition of claim 3 wherein said non-aromatic diester is essentially texanol isobutyrate.
 5. Composition of claim 1 wherein said aromatic diester is essentially succinate.
 6. Composition of claim 1 wherein said hydrocarbon is predominantly alkylbenzenes boiling above about 250° C., said composition containing by weight from about 60% to about 80% prime ester, up to about 30% of said non-aromatic diester, and from about 5% to about 15% of said hydrocarbon.
 7. Composition of claim 6 wherein said non-aromatic diester is essentially texanol ester of C₃ -C₆ alkyl monocarboxylic acid.
 8. Composition of claim 6 wherein the alkyl in said aromatic diester is from C₃ to C₅ and said non-aromatic diester is essentially texanol isobutyrate.
 9. Composition of claim 6 containing by weight from about 65% to about 75% prime ester and from about 15% to about 25% of said non-aromatic diester, said prime ester consisting essentially of said aromatic diester.
 10. Composition of claim 9 wherein said non-aromatic diester is essentially texanol ester of C₃ -C₆ alkyl monocarboxylic acid.
 11. Composition of claim 10 wherein the alkyl in said aromatic diester is from C₃ to C₅ and said hydrocarbon is predominantly monoalkylbenzenes in which the alkyl is from about C₁₀ to about C₁₂.
 12. Composition of claim 9 wherein said non-aromatic diester is essentially texanol isobutyrate.
 13. Composition of claim 9 wherein the alkyl in said aromatic diester is essentially butyl.
 14. A vinyl chloride polymer composition comprising a plasticizing amount of a plasticizer composition of claim
 1. 15. Composition of claim 14 wherein the proportion of prime ester is less than 35 phr.
 16. Composition of claim 15 wherein the proportion of prime ester in said polymer composition is not more than about 30 phr, said non-aromatic diester is essentially texanol ester of C₃ -C₆ alkyl monocarboxylic acid and at least about 60 parts per hundred parts by weight of said prime ester is said aromatic diester, said plasticizer composition containing by weight from about 60% to about 80% prime ester, up to about 30% of said non-aromatic diester and from about 5% to about 15% of said hydrocarbon.
 17. Composition of claim 16 wherein said polymer is essentially polyvinyl chloride and said hydrocarbon is predominantly alkylbenzenes in which the alkyl is from about C₁₀ to about C₁₆.
 18. Composition of claim 14 wherein said polymer is finely divided and essentially uniformly dispersed in said plasticizer composition.
 19. Composition of claim 18 wherein the proportion of prime ester in said polymer composition is less than about 35 phr, the alkyl in said prime ester is from C₃ to C₅, said non-aromatic diester is essentially texanol ester of C₃ -C₆ alkyl monocarboxylic acid and essentially all of said hydrocarbon boils above about 250° C., said plasticizer composition consisting essentially of, by weight, from about 65% to about 75% of said aromatic diester, up to about 30% of said non-aromatic diester and from about 5% to about 15% of said hydrocarbon.
 20. A method for producing a vinyl chloride polymer composition which can be cast in a film on a solid surface, fused and then cooled to provide a solid, plasticized, stain-resistant film on said surface, which method comprises dispersing finely divided particles of said polymer in a plasticizing amount of a plasticizer composition of claim
 1. 21. Method of claim 20 wherein said non-aromatic diester is essentially texanol ester of C₃ -C₆ alkyl monocarboxylic acid and essentially all of said hydrocarbon boils above about 250° C., said plasticizer composition containing by weight from about 60% to about 80% prime ester, up to about 30% of said non-aromatic diester and from about 5% to about 15% of said hydrocarbon. 